1. Field of the Invention
The present invention relates to wireless communication, and more particularly, to an equalizing method and apparatus in a wireless communication system including a relay station.
2. Related Art
A relay technology is a technology of enabling a service to be provided to a service disabled mobile station positioned in a shadow region or improving a data transmission rate. In addition, the relay technology has been prominent as a dominant technology in both of IEEE 802.16m and LTE-Advanced that correspond to candidate technologies of IMT-advanced, which is the next generation mobile communication standard. However, the relay technology should overcome performance deterioration caused by a difference in a propagation time intrinsically existing between a plurality of communication channels.
An orthogonal frequency division multiplexing (OFDM) system in which a relay station is not present prevents inter-symbol interference (ISI) using a cyclic prefix longer than a length of a channel impulse response. When the length of the channel impulse response is longer than a length of the CP, the ISI may be removed using a time domain equalizer (TEQ). However, a method of removing the ISI using the TEQ has a problem that noise is significantly amplified during a process of reducing a length of a channel. In order to solve this problem, a multi tap frequency domain equalizer (FEQ) is used.